To answer your original questions, yes, it helps to have an understanding partner. My H has no experience with dissociative disorders, but he is kind and supportive (most of the time) when I feel bad. When I was depressed, he was patient and kind. I do not think that is too much to ask.

It sounds like you are patient and kind to your bf and he does not do that in return. And it sounds like he will not change.

I guess you have to decide if this is the way you want to live. There is definitely something to be said for hanging in there when your partner is sick. And there is definitely something to be said for helping someone who needs your help. Those things can be satisfying and worthwhile. On the other hand, the fact that someone doesn't beat you is not a great reason to stay in a relationship. And there are plenty of nice people who need help and would be grateful for the help.

I wonder if deciding to take some time off would be helpful for both of you. Perhaps spending one day a week (24 hours) in your own home would help you to see what your days would be like without hi. And vice versa. And I wonder if you could get support when you are feeling depressed from someone else.